In previous work, we showed that RSV encodes three transmembrane glycoprotein, the fusion F glycoprotein involved in viral penetration, the attachment G glycoprotein, and the small hydrophobic SH protein of unknown function. The post-translational processing of the three proteins was studied in parallel. Inhibitors of exocytosis were employed to identify intermediates in processing and to operationally define the intracellular sites of processing steps such as oligomerization, palmitylation, polylactosaminylation, cleavage of the F protein and O-glycosylation of the G protein. Sucrose gradient sedimentation and chemical cross-linking were used to monitor oligomerization, and lectin-binding and endoglycosidases were used to monitor O-glycosylation. One finding was that the oligomerization of the G protein occurs in the endoplasmic reticulum, whereas its O-glycosylation does not occur until the trans Golgi compartment. This implies that the O-linked sugars are not important determinants of oligomerization and, by implication, of polypeptide folding. Studies are continuing to analyze the multiple forms and complex processing scheme of the SH protein using site-directed mutagenesis and biochemical techniques.